Photoproduction of Positive Pions from Protons

Uretsky, Jack L. ; Kenney, Robert W. ; Knapp, Edward A. ; et al.
Phys.Rev.Lett. 1 (1958) 12-14, 1958.
Inspire Record 944927 DOI 10.17182/hepdata.21871

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2 data tables

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Elastic Scattering of Negative Pions by Protons at 230, 290, 370, and 427 Mev

Goodwin, Lester K. ; Kenney, Robert W. ; Perez-Mendez, Victor ;
Phys.Rev. 122 (1961) 655-664, 1961.
Inspire Record 944985 DOI 10.17182/hepdata.26809

The elastic differential cross section for the scattering of negative pions by hydrogen was measured at laboratory-system pion kinetic energies of 230, 290, 370, and 427 Mev. The elastically scattered pions were detected by a counter telescope which discriminated against recoil protons and inelastic pions on the basis of range. Differential cross sections were obtained at nine angles for each energy and were fitted by a least-squares program to a series of Legendre polynomials. At the three higher energies, D waves are required to give satisfactory fits to the data. The real parts of the forward-scattering amplitudes calculated from this experiment are in agreement with the predictions of dispersion theory. The results of this experiment, in conjunction with data from other pion-nucleon scattering experiments, support the hypothesis of charge independence at these higher energies.

4 data tables

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Total Cross Sections for Negative Pions on Protons at 230, 290, 370, 427, and 460 Mev

Caris, John C. ; Goodwin, Lester K. ; Kenney, Robert W. ; et al.
Phys.Rev. 122 (1961) 262-264, 1961.
Inspire Record 944986 DOI 10.17182/hepdata.26810

Total cross sections for negative pions on protons were measured at laboratory energies of 230, 290, 370, 427, and 460 Mev. The measurements were made in the same pion beams as and at energies identical with those of our π−−p differential scattering experiments. Comparisons of the total and differential scattering can be made with the dispersion theory at a given energy without introducing the systematic errors that would normally enter due to uncertainties in the parameters of more than one pion beam. The measured total cross sections are found to agree within statistics with other measured values, and with the sums of elastic, inelastic, and charge-exchange cross sections measured at this laboratory. The results are:

1 data table

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Angular Distributions of Photopions from Hydrogen

Knapp, Edward A. ; Kenney, Robert W. ; Perez-Mendez, Victor ;
Phys.Rev. 114 (1959) 605-611, 1959.
Inspire Record 944992 DOI 10.17182/hepdata.26850

An accurate measurement of the differential cross section for the photoproduction of positive pions from protons has been made at the Berkeley synchrotron for photon energies of 260 and 290 Mev. The mesons were produced in a thin-walled liquid-hydrogen target, and the meson-detection apparatus utilized the characteristic decay of the pion. The measurements were done in two steps, from 0° to 50° with equipment specifically designed to reduce a very high forward-angle positron background, and from 30° to 160° with equipment whose efficiency and solid angle could be accurately determined. The abrupt flattening of the observed cross section in the region forward of 40° is due to "photoelectric ejection" of pions from the cloud surrounding the nucleon. The results are compared to the theory of photo-production derived from the dispersion relations, and the agreement is satisfactory within the limitations of the theory.

2 data tables

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Charge-Exchange Scattering of Negative Pions by Hydrogen at 230, 260, 290, 317, and 371 Mev

Caris, John C. ; Kenney, Robert W. ; Perez-Mendez, Victor ; et al.
Phys.Rev. 121 (1961) 893-904, 1961.
Inspire Record 944987 DOI 10.17182/hepdata.805

The differential cross section for charge-exchange scattering of negative pions by hydrogen has been observed at 230, 260, 290, 317, and 371 Mev. The reaction was observed by detecting one gamma ray from the π0 decay with a scintillation-counter telescope. A least-squares analysis was performed to fit the observations to the function dσdω=Σl=15alPl−1(cosθ) in the c.m. frame. The best fit to our experimental measurements requires only s- and p-wave scattering. The results (in mb) are: The least-squares analysis indicates that d-wave scattering is not established in this energy range.

4 data tables

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Polarization of Recoil Protons in pi + /- p Elastic Scattering Near 600 MeV

Eandi, Richard D. ; Devlin, Thomas J. ; Kenney, Robert W. ; et al.
Phys.Rev. 136 (1964) B536-B542, 1964.
Inspire Record 944968 DOI 10.17182/hepdata.529

Angular distributions of recoil-proton polarization in elastic π±p scattering were measured at 523-, 572-, and 689-MeV incident pion kinetic energy. Polarization measurements were made by observing the azimuthal asymmetry in the subsequent scattering of recoil protons in large carbon-plate spark chambers. Typical strong variation of the polarization with pion scattering angle near the πp diffraction minima was observed. Since existing opinion favors a D13 resonance at 600 MeV, a phase-shift analysis was attempted in order to confirm the existence and parity of this resonance. Available πp total and differential cross sections, these polarization data, and some possible restrictive assumptions related to the 600-MeV resonance were used in the analysis. Though the polarization results aided significantly in restricting the number of acceptable phase-shift sets, still, many plausible and qualitatively different sets were found.

6 data tables

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Polarization of Recoil Protons in pi + /- p Elastic Scattering at 864, 981, and 1301 MeV

Eandi, Richard D. ; Devlin, Thomas J. ; Kenney, Robert W. ; et al.
Phys.Rev. 136 (1964) B1187-B1189, 1964.
Inspire Record 944970 DOI 10.17182/hepdata.535

Angular distributions of recoil-proton polarization in elastic π±p scattering were measured at 864-, 981-, and 1301-MeV incident pion kinetic energy. Polarization measurements were made by observing the azimuthal asymmetry in the subsequent scattering of recoil protons in large carbon-plate spark chambers. The spark chambers proved to be very suitable polarization analyzer detectors. Strong variation of the polarization with backward pion scattering angle was observed.

5 data tables

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Pion-Proton Charge-Exchange Scattering from 500 to 1300 MeV

Chiu, Charles B. ; Eandi, Richard D. ; Helmholz, A.Carl ; et al.
Phys.Rev. 156 (1967) 1415-1426, 1967.
Inspire Record 52278 DOI 10.17182/hepdata.750

Differential cross sections for the reaction π−p→π0n were measured at nine incident-pion kinetic energies in the interval from 500 to 1300 MeV. The negative pion beam from the bevatron was focused on a liquidhydrogen target completely surrounded by a cubic array of six steel-plate spark chambers. The spark chambers were triggered on events with neutral final states. Charge-exchange events were identified from the one-shower and two-shower events in the spark-chamber pictures. By the Monte Carlo technique, the π0 distributions were calculated from the bisector distributions of the two-shower π0 events together with the observed γ-ray distributions of the one-shower π0 events. These π0 distributions were fitted with both Legendre-polynomial expansions and power-series expansions by the method of least squares. The extrapolated forward differential cross sections are in good agreement with the dispersion calculations. The Legendre coefficients for the differential cross sections in isospin state T=12 were obtained by combining our results with available data on π±p elastic scattering. In the light of existing phase-shift solutions, the behavior of these coefficients is discussed. The D5F5 interference term that peaks near 900 MeV is verified to be in isospin state T=12 only. We report here also the total neutral cross sections and the cross sections for the production of neutral multipion final states 2π0n and 3π0n. The 4π solid angle and the calibrated energy response of the spark chambers contribute to the accuracy of the results.

19 data tables

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Mass identified particle production in proton anti-proton collisions at s**(1/2) = 300-GeV, 540-GeV, 1000-GeV, and 1800-GeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Phys.Rev.D 48 (1993) 984-997, 1993.
Inspire Record 363171 DOI 10.17182/hepdata.22669

The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.

11 data tables

PT RANGE FROM 0 TO INFINITY.

PT RANGE FROM 0 TO INFINITY.

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Cross-sections for deuterium, tritium, and helium production in p p collisions at s = 1.8-TeV

Alexopoulos, T. ; Anderson, E.W. ; Biswas, N.N. ; et al.
Phys.Rev.D 62 (2000) 072004, 2000.
Inspire Record 536253 DOI 10.17182/hepdata.22220

We present the results of a search for the production of light elements in p¯p collisions at the Fermilab Tevatron collider. Momentum, time of flight, and dE/dx measurements are used to distinguish nuclei from elementary particles. A production ratio for deuterium to hydrogen is calculated and compared to the primordial value of the big bang model. Some evidence for tritium is found and none for helium isotopes.

3 data tables

Invariant cross section and cross section per unit rapidity interval for deuterium and anti-deuterium production.

Independent measurement of the proton or anti-proton production cross section (K Gulbrandsen, Senior Thesis, University of Wisconsin-Madison 1998).

Measured cross sections for tritium production.